下面的代码显示主菜单的活动子菜单。它近乎完美，但是，我需要它来显示这些子项的所有子项及其子项。又名无限深度。提前感谢！

下面是一个示例，以进一步说明：

WP-主菜单

主页关于新闻（活动菜单项）按社交Facebook，如果我在新闻、新闻、社交、Facebook或Twitter页面，它会显示侧菜单：

这就是我想要的，除了在所有这些页面上，“社交”的两个孩子（Facebook和Twitter也应该出现在社交下）。

class Selective_Walker extends Walker_Nav_Menu
    {
        function walk( $elements, $max_depth) {

            $args = array_slice(func_get_args(), 2);
            $output = \'\';

            if ($max_depth < -1) //invalid parameter
                return $output;

            if (empty($elements)) //nothing to walk
                return $output;

            $id_field = $this->db_fields[\'id\'];
            $parent_field = $this->db_fields[\'parent\'];

            // flat display
            if ( -1 == $max_depth ) {
                $empty_array = array();
                foreach ( $elements as $e )
                    $this->display_element( $e, $empty_array, 1, 0, $args, $output );
                return $output;
            }

            /*
             * need to display in hierarchical order
             * separate elements into two buckets: top level and children elements
             * children_elements is two dimensional array, eg.
             * children_elements[10][] contains all sub-elements whose parent is 10.
             */
            $top_level_elements = array();
            $children_elements  = array();
            foreach ( $elements as $e) {
                if ( 0 == $e->$parent_field )
                    $top_level_elements[] = $e;
                else
                    $children_elements[ $e->$parent_field ][] = $e;
            }

            /*
             * when none of the elements is top level
             * assume the first one must be root of the sub elements
             */
            if ( empty($top_level_elements) ) {

                $first = array_slice( $elements, 0, 1 );
                $root = $first[0];

                $top_level_elements = array();
                $children_elements  = array();
                foreach ( $elements as $e) {
                    if ( $root->$parent_field == $e->$parent_field )
                        $top_level_elements[] = $e;
                    else
                        $children_elements[ $e->$parent_field ][] = $e;
                }
            }

            $current_element_markers = array( \'current-menu-item\', \'current-menu-parent\', \'current-menu-ancestor\' );  //added by continent7
            foreach ( $top_level_elements as $e ){  //changed by continent7
                // descend only on current tree
                $descend_test = array_intersect( $current_element_markers, $e->classes );
                if ( !empty( $descend_test ) ) 
                    $this->display_element( $e, $children_elements, 0, 0, $args, $output );
            }

            /*
             * if we are displaying all levels, and remaining children_elements is not empty,
             * then we got orphans, which should be displayed regardless
             */
             /* removed by continent7
            if ( ( $max_depth == 0 ) && count( $children_elements ) > 0 ) {
                $empty_array = array();
                foreach ( $children_elements as $orphans )
                    foreach( $orphans as $op )
                        $this->display_element( $op, $empty_array, 1, 0, $args, $output );
             }
            */

/*added by alpguneysel  */
                $pos = strpos($output, \'<a\');
            $pos2 = strpos($output, \'a>\');
            $topper= substr($output, 0, $pos).substr($output, $pos2+2);
            $pos3 = strpos($topper, \'>\');
            $lasst=substr($topper, $pos3+1);
            $submenu= substr($lasst, 0, -6);

        return $submenu;
        }
    }